56 * 1 + 66 : 6 = 56 + 11 = 67
13 * (4 + 2) : 1 = 13 * 6 : 1 = 78
78 * 0 + 25 * 3 = 0 + 75 = 75
(27 + 13) * 2 − 78 = 40 * 2 − 78 = 80 − 78 = 2
39 : (7 + 6) * 21 = 39 : 13 * 21 = 3 * 21 = 63
81 − 68 : (9 + 8) = 81 − 68 : 17 = 81 − 4 = 77
(45 + 15) : 15 + 76 = 60 : 15 + 76 = 4 + 76 = 80
80 : 20 * (48 − 48) = 80 : 20 * 0 = 4 * 0 = 0
20 * 3 − (56 + 0) = 60 − 56 = 4